Seeing that you're not surprised, I think you must have known.
- Vu que tu n'es pas surpris, je pense que tu étais au courant.
I was surprised and became sad.
- Je fus surpris et devins triste.
I was amazed at his courage.
- Son courage m'a surprise.
Sorry I startled you!
- Désolé de vous avoir surpris !
Tom was startled by a knock on the door.
- Tom a été surpris par un coup sur la porte.